Tap driver



Sept. 14, 194.8.

H. P. BOGGIS TAP DRIVER Filed March 28, 194g;A

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INVENTUR.

HENRY P. BOGGIS ATTORNEYS Patented Sept. 14, 1948 UNITED STATES PATENTOFFICE 2,449,103 TAP DRIVER YHenry P. Boggis, Shaker Heights, OhioApplication March 28, 1944, Serial No. 528,497

4 Claims. (Cl. 279-55) This invention relates as indicated to tapdrivers and in general to tool holders adapted to directly embrace, indriving communication, tools such as taps which are provided with acylindrical shank and generally a polygonal terminal portion throughwhich the driving forces are transmitted. The cylindrical portion of thetool is required to be maintained in axial alignmentv with the axis ofrotation of the driving means such as a spindle of a drill press or likeequipment. The cylindrical surface of the tool by which such axialalignment may be maintained does not provide for the transmission of thedriving force from the holder to the tool, and accordingly the tool isgenerally provided at its nonoperating end with a polygonal surfacewhich may be square, rectangular, or in the form of a flat tongue.

In the manufacture of tools of this character,

it is quite difficult to maintain in alignment the axis of thecylindrical portion of the tool and the axis of the polygonal portionthrough which driving communication is established. If the holder forthe tool is provided with truly axially aligned portions adapted toembrace the cylindrical and polygonal portions of the tool respectively,the clamping forces to which the tool is subjected in being xed in theholder will result in the setting up in the tool of forces which mayresult in the end thereof being forced out of line, or the setting up ofinternal stresses in the tool itself which are highly undesirable.

It is a principal object of my invention, therefore, to provide astructure which will not only engage the tool in its cylindrical portionand maintain the tool coaxially with the axis ofrotation of the holder,but at the same time, embraces the polygonal portion of the tool andtransmits the driving force thereto without placing the tool under anyof the objectionable stresses above mentioned.

Other objects of my invention will appear as the description proceeds.

To the accomplishment of the foregoing and related ends, said inventionthen comprises the features hereinafter fully described and particularlypointed out in the claims, the following descripton and the annexeddrawing setting forth in detail certain illustrative embodiments of theinvention, these being indicative, however, of but a few of the variousways in which the principle of the invention may be employed.

In said annexed drawing Fig. 1 is a side elevational view partially insection along a vertical plane passing through the longitudinal axis ofthe tool and showing one embodiment of my invention;

Figs. 2, 3 and 4 are transverse sectional views of the structureillustrated in Fig. 1, taken on planes respectively indicated by thelines 2 2, 3 3, and 4 4; 1

Fig. 5 is a perspective View of the floating driven block which is oneof the parts of the assembly illustrated in Fig. 1; and

Fig. 6 is a perspective view of the floating driver block likewisecomprising one of the parts of the assembly illustrated in Fig. 1.

Referring now more specifically to the drawing and more especially toFig. 1, the structure here illustrated comprises a body I which isgenerally cylindricalin form, and to the rear end of which there isintegrally connected a taper or straight shank 2 terminating in aflattened end 3. The shank 2 is coaxial with the axis of the cylindricalportion I of the body and ground to a suitable taper such as a Morsetaper so that the tool may be held in a conventional drilling or tappingmachine.

The forward end 4 of the body I is coniform on its interior and thusadapted to receive a coniform collet 5. The external surface 6 at theend of the body I is a ground cylindrical surface adapted to be closelyembraced by the ground surface 'l on the inside of the nut 8. The openend of the nut 8 is threaded and in threaded engagement with threadsformed at 9 in an intermediate area on the body I. Openings I0 areprovided at clrcumferentially spaced points on the nut 8 and adapted toreceive a tool such as a Spanner wrench to assist in applying andremoving the nut 8 on the body I.

The nut 8 at its forward end is provided with an inwardly extendingflange II having a coniform shoulder I2 adapted to engage acomplementary coniform shoulder on the collet 5.

The collet 5 is centrally provided with a cylindrical opening adapted toclosely embrace and telescopically engage the cylindrical-portion I3 ofa tool such as I4 which is illustrated as a tap. The

' non-operating end I5 of the tool is polygonal in cross-section, theillustrated embodiment being square as most clearly shown in Fig. 3.

The end I5 of the tool is closely embraced in a corresponding openingformed` centrally in the floating driven block I6 whose outer peripheryis cylindrical and of a diameter slightly less than the inside diameterof the body I. In axial alignment with the floating driven block I6 is acylindrical floating driver block4 I'I, the latter being mounted forrelative rotatable and axial movement on a pin I8 carried by the bodyand arranged so that the axis intersects the axis of the body I at rightangles.

As most clearly illustrated in Figs. 5 and 6, the contiguous faces ofthe members I6 and I7 are provided with a, complementary tongue andgroove connection which, in the illustrated embodiment, includes atongue I9 formed on the member I6, and a groove 2i] on the member II.The member I6 has a central aperture 2 I' extend ing therethrough fromthe bottom of the opening which is adapted to receive the end I5 of thetool.

It should be pointed out that the opening the member I6 for thereception of the end I5 of the tool may be a stepped opening so Vas toaccommodate tool-s having ends of different sizes or it may be desirableto provide a series of inter# changeable members I6 each provided with adifferent opening for the reception of such different sizes and shapesof tool ends as the holder may be required to accommodate.

From the foregoing description, it will be obl served that when a toolsuch as a tap" I 4 is assembled in' the holder, the ground complementarycylindrical surfaces on the inside of the nut and the forward end of thebody, and the ground complementary coniiorm surfacesl on the peripheryof the collet and the inside end of the body, and the groundcomplementary cylindrical surfaces on the outside of thev tool and theinside of the ollet, make it possible to -very accurately maintain theaxis of the tool in alignment with the axis Qi the holder. Y

As previously indicated, the driving end l5 of the tool may, however,have its axis out oi align ment with the axis of the cylindrical surfaceI3. Any such nii-salignment will be automatically compensated for by thefloating driving connection which comprises the members l5, i7, and thepin I8. y

By this construction,- drivirig communication is established between theholder and the end of the tool without subjecting the tool to bendingstresses and the like which might otherwise result m'isalignrhentbetween the axes of the cylinf drioal portion i3 and the terminalportion I5 of the tool. Y

i @ther modes of applying the priniple of the invention may be employed;change being made as "aras me details described, provided the fe uresstated in any of the following claims or the eduivalent of such beemployed.

Iuthereiore, particularly point out and dis# tinctly claim as myinvention:

1. A tool holder comprising a body having a driving shank; means formaintaining 'a tool in substantially axial alignment with said shank;and a'oating driving connection between said body and the tool,comprising a transversely ar-` ranged pin said body, a driving blockmovably moiinte'd on said pin, and aoating driven block adapted toengage the end of the tool, and a complementary tongue and grooveconnection between said driving block and driven block.

Y 2; Atool holder comprising a body having a driving shank; means formaintaining a tool in substantially 'axial alignment with said shank;and ariioatingY driving connection between said and a polygonal terminalportion of the tool, comprising a pin in said body, the axis of whichlies in a plane normal to the axis lof said body,

a driving block mounted for rotatable and axial movement on said pin,vsaid block provided with a face normal to the axis of said body, and a.floating driven block adapted to closely embrace the polygonal terminalof the tool and presenting a face closely adjacent and substantiallyparallel to the face on said driving block, and a complementary tongueand groove connection on said faces.

3`. A tool holder comprising a body' including a tapered driving shank;means for maintaining a t-ool in substantially axial alignment With saidshank comprising a collet having coniform telescopic engagement withsaid body and substantially cylindrical telescopic engagement with thetool, and a nut threaded on said body and having close-fittingcylindrical telescopic engagement therewith and engageable with saidcollet to move said collet and Ibody relatively axially; and a floatingdriving connection between said body and a polygonal terminal portion ofthe tool', comprising a pin iii-said body, the axis of which lies in aplane normal to the axis of' said body, a driV-fing block mounted forrotatable and axial movement on said pin, said block provided with aface normal to the axis of said body, and a floating driven blockadapted to closely embrace the polygonal terminal of the tool andpresenting a face closely adjacent and substantially parallel tothe faceon said driving block, and a comple; mentary tongue and grooveconnection on said faces.

4; A tool holder comprising a body having a driving shank, means formaintaining a tooll in substantially axial alignment with said shank,

axially adjacent driving and driven blocks loosely tting within saidbody, said block-s having a complementary tongue and groove lconnect-ionbetween them for permitting relative transverse movement thereof in saidbody, Said driven block being formed Witl a lsoc'lket for drivingengag'- n'et with the etid of the tool, and 'means Slipporting saiddrivingv block for' rotation in unison with said body and for transverseI'n-ovement in said body alongr` a line angularly disposed with respectto the line of transverse movement permitted by the tongue and grooveconnect-ion of said blocks.

HENRY P. B'QCMErIS.n

REFERENCES CITED A`The, following references vare of record in the fileof this patent:

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